Duplex grinding machine



Nov. 19, 1935. J; BATH ET AL DUPLEX GRINDING MACHINE.

Filed March 6, 1933 10 Sheets-Sheet l &/7 m

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Nov. 19, 1935. J. BATH ET AL Filled March e, 1933 10 Shegts-Sheet 7 Nov. 19, 1935. J. BATH ET AL DUPLEX GRINDING MACHINE Filed March e. 1955 1d Sheets-Sheet 8 QNN I ll/I I vr////////// QM .m. WNW 1 N x r \QN ANWK Nov. 19,1935. J. BATH ET AL DUPLEX GRINDING MACHINE Filed March 6, 1933 10 Sheets-Sheet 9 who.

NOV. 19 1935', J BA H ET AL I 2,021,535

DUPLEX GRINDING MACHINE Filed March 6, 1933 10 Sheets-Sheet l0 alongthe Patented Nov.- l9, 1935 -UNITED STATES.

PATENT 1 OFFICE- DUPLEX ammo. mcnmn John Bath and Stanley W. Bath, Shrewsbnry, Massi, assignors to John Bath & Company Worcester,

chusetts Mass, a corporation of Application March c, 195:, Serial No. 659,764

. 10 Claims. This invention relates to a grinding machine of the duplex type in which separate grinding operations may be simultaneously performed on two different pieces of work.

It is the'general object of our invention to improve the construction of such duplex grinding machinesin -manyimportant respects, to the intent that the machine may be more perfectly adapted to its intended purposes.

To the attainment of this general object. one feature of*our invention relates to the provision of an improved power cross feed mechanism for the work table, together with means for separately feeding eitherwheel head manually toward or away from the work.

We also provide power means for giving each wheel head a limited movement toward and away from the work, as for a so-called plunger cut.

Other features of the invention relate to means for disconnecting and manually feeding the work table longitudinally, to an improved double swive1 table construction, and to the provision of improved hydraulic feeding and control mechanism.

Our invention further relates to arrangements 5. and combinations of parts which will be herein- 'the drawinsii, iii which machine; Fig. 2 is a plan view, looking in the direction of the arrow 1 in Flg. 1;

. Fig. 3 is an end elevation, looking in the di-. rectionoithearrowiinl lg.l; I

Fig is a a sectional front elevation, "taken line 4-4 in Fig. 2; Fig 5 is a diagrammatic view of the hydraulic feeding and control mechanism; Fig. Bis an enlarged sectional of a table release device;

Fig. 'l is an enlarged front elevation of certain Fig. l is a front elevation f-our improved front elevation table, feeding mechanism;

the line l2l2 in Fig.

Fla. 7:

10 is a partial plan view of the work slide, with the swivel tables mountedthereon;

Flg: 11 is a partial front elevation, looking in the direction r the arrow H in Fig. 10;

Fig. 12 is a sectional and elevation. taken along Fig. 13 is a side elevation of one of the wheel heads and certain associated parts;

Fig. 14 teen enlarged sectional front elevation, taken along the line-ll-Il in Fig. 13;

Fig. 15 is an enlarged detail side' elevation, 8

taken partly in section along the line li-IS inFlg. 14;

Fig. 16 is'an enlarged sectional detail view ofcertain cam adjusting mechanism, taken along the line I6-l6 in Fig. 15; 10

Fig. 17 is an enlarged side elevation of a cam, partly in section and taken, along the line l'|-l| in Fi 16;

Fig. 18 is a front elevation of the cam, looking in the direction of the arrow 18 in 1'7;

Fig. 19 is a front elevation, partly in section,- showing portions of the two wheel heads and a single grinding wheel jointly supportedv thereby;

20 is a side elevation of certain valve mechanism for efiecting the plunge cut;

Fig. 21 is a sectional diagrammatic view show-' ing a hydraulic actuating and control-mechanism for the plunger cut;

' Fig. 22 shows certain of the parts appearing in Fig. 21 but in a different position, and h 26 Figs. 23 to 28 inclusive illustrate diflerent'uses for our improved machine.

Referring to Figs. 1, 2, and 3, our improved duplex grinding machine comprises a base .er frame F supporting a pair of wheel heads W and 30 W and .a reciprocating table T having work heads H and H. Motors M and M are provided for the wheel heads W and W, additional motors AandAfortheworkheadsHandH' andamo-. torBforthepum'pP(Flg.4). 4 85 Work table We will first describe our improved work table and the associated devices by which two pieces ,of work may be simultaneously mounted and 4 rotated thereon, and by which desired movements of the table, both longitudinally and ly, may be obtained.

The work table T (Figs. 10 to 12) is slidable longitudinally in a V-shaped guideway II in'a'45 support 8 and also on a flat bearing surface It thereof. The support 8 (Fig. 4) is slidable transverseLv on bearing surfaces Ill and lli'of the frame F and is guided by a cross member 1.

A pair of swivel tables 32 and II are pivotedat 3! and II on the table T and are provided withtail stocks 3' and 3] slidable on the swivel I tables 82 and 33 and'secured in adjusted posi- .tion thereon by clamping bolts to. Tail centers dlareslidablein'thetailstocksit'and ll audit screws 3|.

The adjacent ends of the tables 32 and 33 are formed as segmental arcs centered at the pivots 33 and 35, and are provided with arcuate grooves 32 positioned to receive similarly shaped" flanges 33 on a wedge-shaped clamping block 33 secured in position by binding screws 33. The curved end portions of the tables 32 and 33 may be beveled and provided with index marks 33 (Fig. 10) and the clamping block 33 may he graduated as indicated at 31, so that setting of the swivel tables at desired angles may be facilitated.

For the purpose of convenient setting, we alsoprovide each table 32 or 33 with an adjusting screw 33 (Fig. 10) rotatable in a bearing projection 43 on the table T but held from axial movement therein by a collar or shoulder 33. Each adjusting screw 33 is threaded into a swivel nut 3| pivoted at 52 to a mg or bracket 33 projecting When the clamping screws 35 are loosened, the adjusting screws 33 provide convenient means for swinging the tables to any desired angular posi-.

able reduction and change gear driving connections by which the workmay be rotated at desired We have madespecialprovision for disconnectspeeds by the motors A and A. The specific drivingmechanismoithe workheadsHandH forms no part of our present invention and further description thereof appears unnecessary.

Table feed The table '1 is preferably provided with a piston I rod in (Fig.5) connected to a piston u slidable in acylinder32 iixedinthe frame Fandconnected with y li inting m to be deingthetableT i'romthepistcnrodfl whenitis desired to slidethetable Tlongitudinally by hand: For this purpme the rod 33 is provided withan enlarged head 33 (Fig. 6), also with an annulargroove 33 and a cone-shaped end portion 33.

.A latch 33 is mounted on aplunger 3l -slidable'inalaterallymiectingbearingportion -handleverl3ispiwotedatllcnthebracketl2 andhasacamportion'lladaptedtoengagethesecondarmoithebellcrank'll; Whenthehandlever'lflsinthepositicnshow'n in Fig. 5, the'latch 33 isin operative-orlocking positiombutwhentheleverflisswungtothe -positionsho'wnmfulllinesinrig.8,thebell crankllwithdrawsthelatch 33 andrcleasesthe pistcnroduq.

Arack33'(1"igs.7and9)isprovldedonthe imam-mouse table '1'. Ashait'lI (Fig.3) r

ismoimtedinabearingfionanapmnflsecured toarrcntportion oithesupportS. Ahandrwheel: 33isi ixedtotheirontandoftheshatt3I, and apinion 3lisflxedtotherearendo3tbeshai't3l.

from the adjacent and of the swivel table 32 or I may be secured in adjusted position by binding, 4 A gear 33 ismounted on an arm 3'I.securedto one end of a sleeve 33 concentric'with the shaft H and extending through the bearing 32.

An arm 33 is formed on or secured to the outer end of the sleeve 33 and is provided with a spring 5 plunger 33 adapted to be seated in either one oi two holes 3| formed in a'lowerthickened portion or the apron 33. A knob or handle 32 is provided for withdrawing the spring plunger 33. When positioned as shown in Fig. '7, the gear 33 engages the rack 33 and the table T can be moved longitudinally by means of the hand wheel -33 after the table is released from the piston rod 33.

Aiter the table is again connected to the rod 33, the plunger 33 will be placed in the left-hand hole 3| in the apron 33, thus swinging the gear 33 downward out or mesh with the rack 33.

Table cross feed Our improved automatic cross feed for the table 23 T is shown in Figs. 3, l and 8 and comprises a cross feed screw 35 (Fig. 3) rotatable in but held from axial movement relative to bearings 33 and 31 in the frame F and threaded into a nut 33 secured in a depending projection 33 on the table sup- 25 port S. v l

The cross feed screw 35 is connected through a train of gearing I33 to a feed shaft I3I (Fig. 7) having a gear or ratchet wheel I32 iast thereon.

A hand wheel I33 is loosely rotatable about axis of the shaft IN and is detaghably connected to the gear I32 by a pinion mounted at the rear end of a spring-pressed plunger I33. The plunger I33 is slldable axially when it is desired to disconnect the hand wheel from the gear I32 and the plung- 35 er is also connected through intermediate gears (not shown) to an arm I33, also loosely rotatable about the axis of the gear I32 but normally con-- nected to the hand wheel I33 by a stud I33, adapted to be inserted in any one of a series of holes I 31 formed in the hand wheel I33. Ashoulder I33 on the hand wheel engages a stop plate I33 on the apron 33, which stop plate may be placed l imoperative or inoperative position as desired. 5

When the stud I33 is inserted in one of theholes I31 and the pinion on the plunger I33 engages the 'gear I32, the'hand wheel I33 is locked 'to the 7 gear I32. Consequently, when the shoulder I33 -on the hand wheel engages the fixed stop I33,

the gear I32 and cross feed screw 33 'are stopped in a fixed and predetermined position. Iiitisthen desiredtomakeaflne and accurate adjustment of the transverse position of the support 8, the stud I33 iswithdrawn and the arm I33 us turn-' is swung in one direction or the other, ing the pinion'on the plunger'IM rela ve to the gear I32 When the necessary adjustment has been made, the stud I 33 is inserted in another hole I31 andthe' amount of adjustment may be estimated by the number of spaces by which the stud is ad-' vanced. When it is not desired'to stop the cross iced ata predetermined point, the stop plate I33 is withdrawn to inoperative position.

A pawl lever H3 is pivoted at III to a feed lever II2 mounted on a stud II3 on the apron 33 and having a V-shaped cam plate H3 adjust- 1 able -thereon. A spring II3 holdsthe pawl II3 yieldingly in engagement with the ratchet wheel I32 but permits the same to be withdrawn therefrom when manual adjustment is desired. A, spring II3 normally pulls thelever II2 upward to engage a stop pin II'I.

Astud I23 (Fig.3) is supported on an arm I2I clamped on a piston mu m, which we is slidable mounted on a spindle I53 (Fig. 19) rotatable in a in a bearing plate I25 secured to the apron 55 andis connected to-a piston I24 mounted in a cylinder I25 which is also supported on the apron 55. I

Suitable hydraulic connections to be described are provided for admitting fluid under pressure to one end or the other of the cylinder I25, thus giving the piston rod I22 and stud I20 alternate inovements in opposite directions.

The normal position of the parts is as shown in 'Fig. 7, with the stud I20 at one side or the other of the camplate II4. Asthe piston is reciprocated, the stud passes under the high point of the plate I I4 as indicated in Fig. 8, giving the feed lever II2 a feeding movement. The extent of this movement may be varied by adjusting the cam plate H4 in the end of the lever II2.

For this purpose, a screw I25 is mounted for rotation but-not for axial movement in a recess in the cam plate I I4, and is threaded in a hearing portion I25 of the feed'lever 2. By turning the screw I25, the cam plate I I4 may be forced,

outward or drawn inward on guide pins I21, and when thus adjusted, may be secured by a wing .nut I25.

By adjusting the cam plate II4 downward, the stud I25will be engaged earlier and the feed lever H2 and pawl IIO will obviously be given a greater feeding movement.

' Automatiework table travel For automatically controlling and reversing the longitudinal travel of the work table-T, we pro- -vide control mechanismC (Fig. 7- which is.con-. nected to the pump P by an inlet pipe I40 (Fig.

" 5) and which is connected by an exhaust pipe f I to.a.tank I42 from which the pump P draws. liquid supply through a feed pipe I45.

The controL mechanismis also connected by a pipe I44 to one end of the table operating cylinder 52 and by a pipe I45 to the opposite end of the cylinder 52. An automatic reversing and manual control lever or handle L (Fig. '1) projects upward from the controlmechanism C and is alter nately engaged by reversing dogs I45 and I41, mounted for longitudinal adjustment in a If-shaped slot I45 ,(Fig. 12) in the edge of the tableT. 1'

Reversing or' tripvalves I55 and IN (Fig. '7)

are connected for actuation by the handle L and control the reversal of the hydraulic connections to the cylinder pipes I44 and I45. '5. speed con-' trol valve (not shown) is also provided, which may be adjusted manually by moving an arm I55 to, a position corresponding to a, selected graduation on the scale I54.

The details ofgthis speed control and reversing mechanism are not shown or claimed herein, as

this mechanism forms part of the subject-matter of the prior application of Stanley W. Bath, BeriaL No. 611,881, filed May 17, 1932 now U. SQLetters Patent No. 1,946,348, granted February 6, 1934, to which patent reference plete description.

Wfieelslides and feeding mechanism therefor apply also to the wheel 'head w'.

The wheel head w comprises a wheelslidem (Figs. 13 and 14) siidable forward and rearward in aguideway I;I and on aguiding surface I52,

both formed on the 'frame v,F. A wheel-x is is made for a more combe moved outward a short distance for apurpose to be described.

Ordinarily a separate grinding wheel X will be provided for each wheel head and will separately engage the work. It may at times be desirable,

however, to use a single wide-face wheel K (Fig. 15

19), and to support this single wheel between'the two wheel spindles I53, so that the power of both motors M and M may be utilized to drive the single wide wheel.

.When it is desired to operatein this manner, we 20 provide a spindle extension I10 for each spindle I65, said extension being accurately centered on a conical end portion of the spindle and being firmly secured thereon by a washer or collar Ill and binding nut I12.

The wheel. X is preferably provided with hub members I15, inserted from each side of the wheel and accurately centered therewith. These hub members are firmly secured together by binding screws I15 and are preferably recessedto receive projecting end portions Il1- of the spindle extensions I10. The extensions I10 are firmly secured to the hub members I15 by binding screws I 15" after the wheel spindles have been adjusted forward or rearward into accurate alignment.

Clamping screws I50 (Fig. 19) are provided for securing the wheel heads I50 in such aligned p ositiqis. 'Either spindle I55 may be withdrawn axiallyby' the associated handle I55 to permit insertion or removal of the wheel X.

when thus supported, it will be evident that the wheel X is in effect mounted on a long wheel shaft having spaced bearings of substantial extent, said shaft being driven from each end by separate belts I55 and motors M and M. We are thus able to more firmly support and drive the wheel in engagenient with thework K.

Wheel feed Mam Referring particularly to Figs. 13 to 18, we will now describe the mechanism for feeding the wheels x, toward and from the work K. For this purpose each wheel slide I50 is provided with a lead screw I54 (Fig. 15) rotatable in but held from axial movement relative to a at the rear of the wheel slide I50.

The lead screw I 54 is' connected bya bevel sear I and bevel pinion I51 to a feed shaft? I55 extending upwardly and forwardly and supported in bearings m onthe wheel slide I50, said shaft 2 being provided with .a handle I50 at its upper I forward end. The forward end 'of the bearing I55 may be enlarged, as indicated at' I5I, to provides graduated. scale with reference to which the extent of manual movement IQII may be noted; I The lead screw I54 is threadedintd a nut, I55

" (Fig. 15) which is clamped in posltiondn a block I54 slidable -in 'a. dove-tailed guide'way I55 (Fig. 14 m the frame F. The block n has depending arms I55 provided with rolls.I51 engag'ing' opposite sides oi a cam 250. (Fig. 17). The cam f 255- is given intermittent oscillating movements bymechanismtobedescribedandineverypositipn deter-mince the location of the block m :1

bearing I55 55 v the handle the forward roll I31 and lead screw nut I33. Assuming that the block and not are held stationary. movement of the handle I34 manually advances or withdraws the wheel with respect to the work K..

The cam 230 is of a special construction more particularly disclosed in Figs. 14 to 18. The cam is mounted on asleeve 2l| rotatable in bearings 202 (Figs. 14 and 16) in the frame F, and is provided with an arm 203 fixed to the sleeve 20| and connected at its outer end by a'link 204 (Fig. 13) to the outer end of a piston rod' 205 connected to a piston -20 slidable in a fixed cylinder 201.

As fluid under pressure is admitted to one end or the other of the cylinder 201 through control mechanism to be described, the piston will be moved in thecylinder and will cause a corresponding rocking movement of the cam 200.

The cam 200 comprises inner concentric portions 2|0, a raised portion 2| I, an outer concentric portion 2I2 and a movable cam plate 2I3 pivoted at 2 to the concentric portion 2|2 of the cam 200. The cam plate 2|3 has a portion 2|5 which is concentric with the pivot bearing 2 thereof and also has a portion 2|0 which merges at one end with the outer concentric portion 2|2 of the cm 200 but which at the other end is eccentric thereto and positioned at a less distance from the axis of the cam 200.

The movable cam member 2|3.also has an abruptly rising portion 2". and an arm 2|0 provided with a stud 2|! extending through a slot 220 (Fig. 16) to the interior of the sleeve 20I. A spring plate 22| extends laterally from the stud 2i! and is secured to the outer surface of the sleeve 20I as clearly shown in Figs. 16 and 17, this spring acting to force the stud 2i! and arm 2|0 inward towards the axisof the sleeve. A plunger 224 is mounted within. the sleeve' 20| and is provided with 3,00116-8118130d end 225 engaging the inner end of thestud 2l3.

At its opposite end, the pllmger 224 is provided with a threaded portion meshing with an internal screw thread of the sleeve :2" and is further. provided with a squared end 225extending outward through a square opening in an arm 221. The arm 221 is rotatably mounted on the outer end of the sleeve 20| and is connected to the arm 203 by a spring plunger 223. Byavithdrawing the spring pllmger 223 (Fig. 14) the arm 221 may be rotated while the sleeve 20| remains in fixed position, thusadiusting the plunger 224 'axially of the sleeve.

If the plunger ismoved inward, the stud 2 I3 andcamarm 2|8'willbemovedmitward,sotliat the portion 2I5 of the cam member -2|3 more nearly approaches the concentric surface 2I2, thereby reducingthe rate of wheel feed after 1 1 the surface of the portion 2|5.

This method'of feed isusedwhena wheel is to be moved directly forward against the work for a so-called plunge-cut" without axial feed of the wheel or work. r 5 In the normal or rearward position of the block I94, the rear roll I31 is by the inclined face of the portion 2 of the cam'200 and the block I54 is thus held in withdrawn and fixed position.

If a"plunge cut" is desired, fluid under'presr extension of the piston rod 205.

crank 251 to the arm 262 and holds these parts idly toward the work. This preliminary movement may be of substantial extent, usually about one-quarter of an inch. r

The parts are so adjusted that the forward roll I31 will be engaged by the surface 2l5 of 5 'the cam member 2| 3 as the wheel engages the The mechanism by which the liquid suppliedto v the cylinder 201 is controlled is'shown in Figs. 20 20 to 22. This mechanism is connected by an inlet pipe 230 to the liquid supplypipe I40 previously described and is likewise connected by an exhaust pipe 23! to the storage tank I42 (Fig. 5). It will be understood that there is a cylinder 201 for 5 includes a speed valve 233 (Fig. 21), a reversing 30,

valve 234 and a pair of trip valves 235 and 236.

, The reversing valve cylinder 231 is connectedby a pipe 230 to one end of the cylinder 201 and by a pipe 233 to the opposite end of the cylinder 201.

The reversing valve cylinder 231 is also connected 35 by branch pipes 240 and 2 to a pipe 242 which in turn connects with the exhaust pipe 23L The pipe 242' also connects to a port in the cas ing of the trip valve cylinder 243 and an additional pipe 244 connects another port inthe cylin 40 der 243 to one 'end of the reversing valve cylinder 231. The cylinder 245 for the trip valve 235 is similarly connected by a pipe 246 to the exhaust and by a pipe 241 to the opposite end of the reversing valve cylinder 231.

The inletpipe 230 is connected by branch pipes 254 and 25I to ports in the trip valve cylinders 243 and 245 respectively, and the inlet pipe 230 is also connected through the speed control valve 233 and through'a branch pipe 253 to an additional port in the center'of the length of the re.- versing valve cylinder 231.

. The trip valve 235 is provided with recesses 255 and 255 and with a bell crank lever 251 (Fig. 20) secured to one end thereof and by which the valve may be operated. -The trip valve 236 is similarly provided ,with recesses 260 and 26I and with an arm 202 adapted to be engaged by an A tension spring 254 (Fig. 20) connectsthe bell 6 normally against stop pins 255 and 265. When the trip valves are in normal position, pressure is applied through the pipes. 244 and 241 to both ends of the reversing valve cylinder 231, so that there-'- 'versing valve 234 is under equal pressures in both directions and there is no unbalancedforce tending to move the valve.

Operation of wheel feed control A 'piston m (Fig. 20) in a small cylinder :11 is connected by a piston rod 212 to the bell crank 251 of the trip valve 235. Fluid under pressure is supplied through a pipe 213 and is controlled by. a manually operated valve 214 which may be conveniently located at the front of the machine.

in opera- 1&-

When it is desired to set the automatic wheel feed in operation, the valve 214 is temporarily opened to admit pressure to the cylinder 21 i, thus rocking the trip valve 235 in ananti-clockwise direction. The pipe 244 is thus connected to the exhaust pipe 242, while pressure is maintained in the pipe24'1 at the opposite end of the reversing valve cylinder 231. The reversing valve 234 is thus moved from the position shown in Fig. 21

to that shown in Fig. 22 I Liquid under pressure then flows from the pipe 253 through the cylinder 231 to the pipe 239 connected to the left-hand end of the feed cam operating cylinder 201. This'causes the piston 206 to move to the right in Fig. 21, giving the cam 200 a clockwise feeding movement as indicated by the arrow a in Fig. 17.

As this movement of the piston 206 to the right approaches completion. the projecting end of the piston rod 205 engages the trip valve arm 262 and.

3'0 valve 234 is immediately returned to the position shownin Fig. 21, connecting the pressure pipe 253 through the pipe 238 to the right-hand end of the cylinder 201 and moving the piston 206 to the left andback to initial position. 3

1 It will thus appear that fora single momentary opening of the valve 214, the cam 200 will be given an operative clockwise feeding movement followed automatically by-a return movement to initial position.

may be adjusted to control the rate of exhaust from the reversing valve cylinder 231 and thus control the rate of valve travel.

The speedvalve 233 (Fig. 21) is provided with acentral passage 211 and with a series of radial passages 218 of different cross sectional areas. The speed valve 233 may be turned by a handle 219 to bring any selected radial passage 216 in alignment with the pipe 253, thus varying the rate of flow to the cylinder 205. A graduated dial 230 is preferably associated with the handle 219.

General hi draulic operation by which the flow of liquid through the pipes I44 60. and I45 to the main cylinder 62 is controlled. A v relief valve 232 (Fig. 5) prevents the building up of excessive pressure in the feed pipe I40.

- The cross feeding cylinder I25 for thework 4, able support 8 is connected in parallel with the 66 main cylinder 62 so that the piston I24 (Fig. 8)

receives movements'at the same time and in the same direction as the main piston 6 I By reference to Figs. 2 and 8 it will be seen that movement of the piston i24'in either direction 70 eiiects an advance or feeding movement of the gear or ratchet'wheel I02, so that the cross feed operates at each reversalof the work'table travel. pipe 230-and exhaust pipe 23I for the wheel feed cylinders 201 are continuously con.- 15' to the feed pipe .I40 and to the exhaust,

Valves 215 and 21s in the pipes 242 and m so that' the wheel feedcylinders 201 may be started in operation at anytime.

We also preferably provide wheel truing de I vices D and D (Fig.5) connected to the feed pipe 230 and exhaust pipe 23I and operable'by 5 hydraulic mechanism under the control of the operator. H

General (mention Our improved grinding machine has a very wide range of utility and is extremely flexible in its operation, due particularly to the provision or separately swiveled tables and .to the provision of separately controlled wheel feed mechanism for each wheel head.

As previously explained, both wheel spindles may be utilized to drive a single wide face grinding wheel as shown in Fig. 19, and in Figs. 23 to 28 we have shown a series of combinations by which the wide adaptability ofthe machine is v illustrated. g

In Fig. 23 both grinding wheels x= and X are employed in making plunge cuts with'outrela tive axial movement of the wheel'and work, and the two pieces of work are rotated onvthe same axis.

In Fig. 24 the wheel X is grinding a cylindrical surface while the wheel X is grinding a conical surface at the same time, one swiy'el table having been adjusted to produce the conical surface.

In Fig. 25 the wheel x is grinding a conical surface of one taper and one diameter,.while the wheel X is grinding a conical surface of a differ? ent taper and diameter.

In Fig. 26 both wheels are grinding cylindrical 5 work but of diflerent diameters, and in Fig. 27 3 the wheels are of diife'rent widthsand are grinding conical surfaces of difierent diameters and different tapers. I

In Fig. 28 the wheel I! is grinding a straight cylindrical surface and the wheel X aconical surface and both surfaces are being ground simultaneously as the work table reciprocates'. It will be obvious that the number of possible combinations for which our machine is adap is practically unlimited.- The machine may be operated with orwithout longitudinal table feed, either manual or automatic, with an automatic cross feed of the table, with manual wheel feed of either grinding wheel, and also with an automatic advance and return movement of eithen grinding wheel. I

- Suitable provision hasbeen made also for varying the rate" of feed of the variousfeeding devices. v

While we have shown our invention embodied in a machine for grinding work on centers, it will be obvious that many features of the invention are'not limited in their utility to such a machine but may be utilized in other types at grinding machines such as centerless grinders or machines in which the work is chucked.

Having thus described our invention and the advantages thereof, we do not wish to be. limited the details herein disclosed, otherwise than as set forth in the claims, but what we claim is:

LA 7 grinding machine having "a wheel, a wheel head, means to move. said wheel head toward and from the work. a 'work table, an. support for said table, automatic means to move .said tablelongitudinally, and automatic means 7 to feed said support toward said grinding wheel. at each reversal of table travel, said automatic means including a hydraulic cylinder and piston to move said work table longitudinally,- and an additional hydraulic cylinder and pistontoactuate said support-feeding means, said two cylinders being connected in parallel and operating simultaneously. at the beginning of each table movement after each reversal of table travel. 2. A grinding machine having agrinding wheel, a wheel head, manual means to move said wheel head toward and from the work, and hydraulically actuated automatic means to advance said wheel to-a predetermined position and to thereafter withdraw said wheel and hold said wheel in withdrawn position, said automatic means including a rotating cam, connections through which said cam -is effective to move said wheel head, and connections through which said automatic means gives said cam successive angular movements in opposite directions and "brings said cam to rest in initial position.

3. A grinding machine having a grinding wheel,-a wheel head, manual means to move said wheel head-toward and from the work, and

hydraulically actuated automatic means to advance said wheel to a predetermined position and to thereafter withdraw said wheel and hold -wheel head, said feeding mechanism including a hydrauliccylinder and piston, manual means to start said piston in one direction, automatic means to reverse the direction of movement of said piston at the end of its travel in said first direction, and automatic means to bring said piston torest on its return to initial position,

i said hydraulic mechanism including'a reversing valve, amanually operated trip valve therefor, an automatically operated reversing trip valve therefor, and automatic means to restore both trip valves to positions in which they subject said reversing valve to, equal and mutually neutralized pressures on both ends.

5. In a grinding machine, a grinding wheel, a wheel head and feeding mechanism for said wheel head, 'sai d feeding mechanism including a hydraulic cylinder and piston, manual means to start said piston in one direction, automatic meanstoreverse thedirectionofmovement of saidpistonattheendofitstravelinsaidflrst direction, and automatic means to bring said piston to rest on its return to initial positim, said hydraulic means including a reversing valve, 5 a pair of trip valves for said reversing valve and a single spring eil'ective to normally move both trip valves to positions to connect the opposite ends of said reversing valve to equally opposed pressures whereby said reversing valve remains 10.

in fixed position until further movement of one of said trip valves.

6. In a grinding machine, a work table, and a pair of swivel tables mounted on said work table and separately adjustable thereon, adja- 15 r cent ends of said swivel tables having tailstocks and separately adjustable thereon, said swivel tables being pivoted to said work table near their 30 centers and being clamped to said work table at their inner and adjacent ends. I

9. Ina grindingmachine, aworktable,apair of swivel tables mounted on said work table and separately adjustable angularly thereon, means 35 v to secure each swivel table in separate angularly adjusted positions on said work table, and a sep- .to feed said support toward and away from the grinding wheel, to feed said work table longitudinally, and to feed said grinding wheel toward and away from the. work.

JOHN ns'rn. s'rsnmv wan-i1. 

